The anti-sigma factors

Annu Rev Microbiol. 1998;52:231-86. doi: 10.1146/annurev.micro.52.1.231.


A mechanism for regulating gene expression at the level of transcription utilizes an antagonist of the sigma transcription factor known as the anti-sigma (anti-sigma) factor. The cytoplasmic class of anti-sigma factors has been well characterized. The class includes AsiA form bacteriophage T4, which inhibits Escherichia coli sigma 70; FlgM, present in both gram-positive and gram-negative bacteria, which inhibits the flagella sigma factor sigma 28; SpoIIAB, which inhibits the sporulation-specific sigma factor, sigma F and sigma G, of Bacillus subtilis; RbsW of B. subtilis, which inhibits stress response sigma factor sigma B; and DnaK, a general regulator of the heat shock response, which in bacteria inhibits the heat shock sigma factor sigma 32. In addition to this class of well-characterized cytoplasmic anti-sigma factors, a new class of homologous, inner-membrane-bound anti-sigma factors has recently been discovered in a variety of eubacteria. This new class of anti-sigma factors regulates the expression of so-called extracytoplasmic functions, and hence is known as the ECF subfamily of anti-sigma factors. The range of cell processes regulated by anti-sigma factors is highly varied and includes bacteriophage phage growth, sporulation, stress response, flagellar biosynthesis, pigment production, ion transport, and virulence.

Publication types

  • Review

MeSH terms

  • Bacterial Outer Membrane Proteins / pharmacology
  • Bacterial Proteins / pharmacology
  • Bacterial Proteins / physiology
  • Bacteriophage T4 / chemistry
  • Carrier Proteins / pharmacology
  • Carrier Proteins / physiology
  • DNA-Binding Proteins / pharmacology
  • Escherichia coli / chemistry
  • Escherichia coli Proteins*
  • Flagella / chemistry
  • HSP70 Heat-Shock Proteins / pharmacology
  • HSP70 Heat-Shock Proteins / physiology
  • Membrane Proteins / pharmacology
  • Membrane Transport Proteins*
  • Myxococcus xanthus / chemistry
  • Photobacterium / chemistry
  • Pseudomonas aeruginosa / chemistry
  • Pseudomonas aeruginosa / pathogenicity
  • Salmonella / pathogenicity
  • Sigma Factor / antagonists & inhibitors*
  • Sigma Factor / pharmacology
  • Sigma Factor / physiology
  • Spores, Bacterial / chemistry
  • Transcription Factors / pharmacology
  • Transcription Factors / physiology
  • Viral Proteins / pharmacology
  • Viral Proteins / physiology
  • Virulence


  • AlgU protein, Pseudomonas aeruginosa
  • AsiA protein, Enterobacteria phage T4
  • Bacterial Outer Membrane Proteins
  • Bacterial Proteins
  • CarR protein, Azospirillum brasilense
  • Carrier Proteins
  • DNA-Binding Proteins
  • Escherichia coli Proteins
  • FecI protein, E coli
  • FecR protein, E coli
  • FliA protein, Bacteria
  • HSP70 Heat-Shock Proteins
  • Membrane Proteins
  • Membrane Transport Proteins
  • MucA protein, Bacteria
  • PupI protein, Pseudomonas putida
  • PupR protein, Pseudomonas putida
  • RsbW protein, bacteria
  • Sigma Factor
  • Transcription Factors
  • Viral Proteins
  • spoIIR protein, Bacillus subtilis
  • spore-specific proteins, Bacillus
  • sporulation-specific sigma factors
  • FlgM protein, Bacteria
  • dnaK protein, E coli